The present invention generally relates to semiconductor devices and more particularly to a semiconductor device having a multilayer interconnection structure.
Conventionally, increase of operational speed of semiconductor devices is attempted by way of miniaturizing the semiconductor devices according to so-called scaling law.
Meanwhile, in recent high-density semiconductor integrated circuits, a multilayer interconnection structure is used commonly for interconnecting individual semiconductor devices included in the integrated circuit.
In such a multilayer interconnection structure, the separation between adjacent interconnection patterns is reduced inside the multilayer interconnection structure as a result of device miniaturization, and there arises the problem of signal delay caused by parasitic capacitance formed between the interconnection patterns, particularly in the case of recent, highly miniaturized advanced semiconductor integrated circuits.
Thus, intensive investigations have been made for reducing the problem of signal delay caused by the multilayer interconnection structure, by using a low-dielectric constant film (so-called low-K film) such as an organic insulation film of hydrocarbon system or fluorocarbon system for the insulation film used for the interlayer insulation film of the multilayer interconnection structure, in place of using the conventional interlayer insulation film of the SiO2 system, and further by using a low resistance conductor such as copper (Cu) for the interconnection pattern, in place of conventional Al.
Such an organic insulation film generally has a dielectric constant of 2.3-2.5, while it should be noted that this value is lower than the dielectric constant of a conventional SiO2 interlayer insulation film by 40-50% or more.
A low dielectric constant film generally has a small density, and because of this, there is a tendency of having problems such as poor adhesion to interconnection pattern, poor resistance to humidity, and the like associated with the use of the low-dielectric interlayer insulation film.